1. Field of the Invention
This invention relates to novel chemical compounds, and more particularly, it relates to novel sulfam(na)phthaleins derived from perhalomethylcarbinol-substituted naphthols and phenols which are useful as indicator dyes or as light-screening dyes in photographic products and processes.
2. Description of the Prior Art
It is well known that photographic film, and especially multicolor films, may and generally do vary from lot to lot, notwithstanding efforts to "repeat" previous films. Manufacturers of multicolor photographic films have developed a number of procedures to minimize the effects upon the final multicolor image of unavoidable variations in the manufacturing operations. These variations are reflected primarily in shifts in color balance as reflected in mismatching of the D log E curves of the individual red, green and blue exposures. Equipment used to coat multicolor films is highly precise but variations between intended coverage of silver halide and/or the dye image-forming materials do occur. Repeat batches of silver halide emulsions may, and usually do, vary in their photographic response. Individual layers may be dried to slightly different degrees. Films are stored for a period of time after coating to allow the films to "age", so that changes in sensitometry following coating have an opportunity to reach a plateau prior to sale. If the film is designed to be developed by a photofinisher or in a darkroom, processing of the exposed multicolor film is controlled within very narrow limits, typically within plus or minus a half degree of a prescribed temperature, in order to minimize sensitometric variations from film to film. Where the multicolor film is of the negative type, an opportunity to adjust the sensitometry occurs in printing the desired final positive image, during which operation the printing exposure may be appropriately color filtered.
The basic sources of sensitometric variations noted above exist also in multicolor diffusion transfer films, with the added complication that once the film is shipped, the sensitometric properties are essentially fixed. The opportunity for adjustment provided in darkroom processing, practically speaking, is unavailable for users of self-developing films. While professional and advanced amateur photographers may be skillful enough to utilize color correction filters to at least partially "rebalance" the color balance, ordinary users of the film would only be confused by such additional operations.
It is well known to use light-screening dyes in photographic elements. Such a dye may be incorporated as a filter dye in a light-sensitive emulsion layer(s) or in a layer coated over one or more light-sensitive emulsion layers or between two differently color-sensitized emulsion layers to modify the light record in the emulsion layer or to control the spectral composition of light falling on the underlying light-sensitive layer, or it may be incorporated as an antihalation dye in a non-light-sensitive layer positioned on either side of a support carrying the light-sensitive layer(s).
The dyes employed for these purposes, in addition to having the requisite spectral absorption characteristics for their intended use, should be photochemically inert, that is, they should not have any adverse effect on the properties of the light-sensitive emulsion layer(s), and also, they should be capable of being decolorized or removed during photographic processing so as not to leave stain in the processed photographic element. In photographic processes where the dye is removed by being dissolved in a processing solution, it is usually preferred that the dye also decolorize in order to avoid contamination of the processing solution and to prevent staining from residual dye in the processed light-sensitive element.
Though various classes of dyes have been proposed for use in antihalation and color correction filter layers, the dyes heretofore employed have not been altogether satisfactory. Some of the dyes tend to reduce sensitivity, fog or exert other adverse effect on the light-sensitive material. However, the major drawback of previously employed dyes is their tendency to cause stain due to incomplete decolorization or reversal of some of the decolorized form to the original colored form. For example, some classes of dyes rely on the presence of a reagent, such as, a sulfite for "bleaching", i.e., decolorization and unless the dyes are removed from the light-sensitive material during or after processing, their color may reappear with a reduction in sulfite concentration.
Copending U.S. Patent Applications Ser. Nos. 835,998 now No. 4,178,446; 836,005; 836,009; and 836,021 now No. 4,204,061 of Stanley M. Bloom, Alan L. Borror and James W. Foley, all filed September 23, 1977, are directed to 3,3-disubstituted-sulfam(na)phthaleins possessing as a 2-substituent, respectively, a --CO.sub.2 (CH.sub.2).sub.2 Y moiety wherein Y is an electron-withdrawing group; a ##STR3## moiety wherein Y' is bromo or chloro; a --CO.sub.2 R' moiety wherein R' is substituted or unsubstituted alkyl or phenyl; and a --COR" moiety wherein R" is substituted or unsubstituted alkyl or phenyl. In these 2-substituted-sulfam(na)phthaleins, one of the 3-substituents may be a 4'-hydroxy-1'-phenyl moiety or a 4'-hydroxy-1'-naphthyl moiety and the other 3-substituent may be, for example, a phenyl moiety unsubstituted or substituted with one or more groups, such as, hydroxy, alkyl, alkoxy, dialkylamino or a fused substituent, e.g., [ij]quinolizidine.
As discussed in the aforementioned applications, such compounds have a colorless form below a given alkaline pH and in the presence of base above said alkaline pH, generate a colored, i.e., light-absorbing form. Depending upon the 2-substituent of the sulfam(na)phthalein ring, some of the compounds function as classical pH-sensitive dyes and the light-absorbing form is decolorized by reversal to the original colorless precursor which is effected by reducing the pH below said alkaline pH. The remaining compounds are rendered colorless without reversal to the original colorless precursor and without a pH reduction and decolorize by undergoing an irreversible cleavage reaction with base at a pH above said alkaline pH to yield a colorless product.
The present invention is concerned with a novel class of sulfam(na)phthaleins derived from 2-perhalomethylcarbinol-substituted 1-naphthols or phenols. In a preferred embodiment, the present invention is concenred with sulfam(na)phthaleins that are initially colored and which find utility as light-screening dyes in photography.